MiniSonic Measuring Microphones

Lindos miniature electret microphones are calibrated to UniSon-Mic standard and fitted with Minijacks for plugging directly into the MiniSonic MS1/MS10/MS20 test set. This allows precision measurement of loud speakers, room responses and other microphones. The MM1 and MM3 are both classed as "1/4 inch" mics (standard 7mm external diameter).

We favour the use of quarter inch mics, because, being small compared to the wavelength even at 20kHz (wavelength 18mm) they do not need to be pointed accurately at the source (omnidirectional), and do not disturb the propagating waves in free-field measurement as bigger microphones can.

The fact that calibrated mics can be plugged directly into the MiniSonic unit, without the need for a pre-amplifier or phantom power source, makes instant speaker measurements possible at last.

The MiniSonic units have dual (stereo) mic inputs for two reasons. Firstly, it is very easy to compare miniature mics (using the difference plot facility on Lin4Win) and even to compare traditional mics (using the line input too). Secondly, using two Lindos miniature mics, the MiniSonic becomes a 'purist' recording front end (spaced omni technique), or camcorder adaptor for interviews, with precision 1dB gain setting facility and PPM level monitoring.

Lindos MS20

The Calibration Process

Lindos mics are all calibrated using a pressure calibrator, which consists of a sealed tube with a tone generator at one end and the mic under test well sealed at the other. This provides a tight coupling between the tone generator and the mic's diaphragm that ensures a constant energy transfer independant of any reverberant sound in the room. While generating a 1kHz tone the output voltage/level is measured and this reading is used to select appropriate resistors for a potential divider (arranged inside a gold plated minijack) to attenuate the output voltage such that -30dBu (24.5mV) is output for 100dBSPL (2 Pa) i.e. our microphones are calibrated to a sensitivity of 12.25mV/Pa. Our calibrator operates at a fixed level of 114dBSPL.

Lindos MM3

The MM3 is recommended for most measurement purposes as it has particularly flat frequency response.

Click here to see best case test results for the MM3s.Click here to see worst case test results for the MM3.

Lindos MS20

Specification

Frequency Response

Typically ±2dB, 20Hz-20kHz (±1dB 40Hz-15kHz)

Sensitivity

-30dBu out for 100dBSPL (UniSon-Mic standard)

Noise Level

42dBSPL 468-weighted, 30dBA(SPL) typical

Clipping Level

125dBSPL (-32dB Distortion Residue)

Distortion Residue

-46dB at 100dBSPL, -40dB at 110dBSPL, -37dB at 115dBSPL

Power

5v 0.5mA on jack tip (as per UniSon-mic standard)

Cable Length

3m

Load R

100k min for accurate calibration

Lindos MM1

The MM1 is a Lindos calibrated Beyer Dynamic MCE5.09. Lindos recommends using this mic for close micing and lapel interview use. It features 'presence' boost of around 6dB peaking at 12kHz, which assists high frequency pick-up for lapel use. Supplied with a grill, wind shield and a lapel mounting clip.

"In short, I love it. Extremely useful; wonderfully succinct -- I've been looking for a tool like this for 20 years."

Phillip Sztenderowicz,Technical Department,Sterling Sound

About Lindos Electronics

Lindos Electronics has made audio test sets for more than 30 years. A small British firm, we're passionate about high quality audio. We're trusted by big players like Sony and the BBC to test the performance of their audio equipment, and now we're passing on our audio expertise to the recording industry with the creation of the Minisonic Mic Kit.